Surgical stapling apparatus

ABSTRACT

A surgical stapling apparatus includes a cartridge assembly defining a tissue contacting surface; an anvil assembly defining a tissue contacting surface; and a surgical buttress releasably secured to at least one of the tissue contacting surface of the cartridge assembly and the tissue contacting surface of the anvil assembly by at least one anchor. A loading unit includes a surgical buttress releasably secured to an anvil assembly and/or a staple cartridge secured thereto by at least one anchor, and a drive assembly including a knife blade, wherein movement of the drive assembly from a proximal position to a distal position results in the knife blade cutting the at least one anchor and freeing each surgical buttress from the anvil assembly and/or cartridge assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/170,377, filed Oct. 25, 2018, which is acontinuation application of U.S. patent application Ser. No. 14/934,192,filed Nov. 6, 2015, now U.S. Pat. No. 10,111,659, which is acontinuation of U.S. patent application Ser. No. 13/799,357, filed Mar.13, 2013, now U.S. Pat. No. 9,192,380, which is a continuation of U.S.patent application Ser. No. 12/528,526, filed Aug. 25, 2009, now U.S.Pat. No. 8,413,871, which is a National Stage Application ofPCT/US2008/002981, filed Mar. 5, 2008, under 35 U.S.C. § 371 (a), whichclaims priority to U.S. Provisional Patent Application Ser. No.60/905,566 filed Mar. 6, 2007, the disclosures of each of theabove-identified applications are hereby incorporated by reference intheir entirety.

BACKGROUND Technical Field

The present disclosure relates to a surgical apparatus, e.g., a surgicalstapling apparatus. More particularly, the present disclosure relates toa surgical stapling apparatus including a detachable surgical buttressand/or an endoscopic surgical stapling apparatus that includes adetachable surgical buttress for a loading unit, e.g., a single useloading unit (“SULU”) or disposable loading unit (“DLU”). Forsimplicity, hereinafter, SULU or DLU will be referred to as “DLU”, butit should be understood to include either or both a DLU or SULU.

Background of Related Art

Surgical devices wherein tissue is first grasped or clamped betweenopposing jaw structure and then joined by surgical fasteners are wellknown in the art. In some instruments a knife is provided to cut thetissue which has been joined by the fasteners. The fasteners aretypically in the form of surgical staples but two part polymericfasteners can also be utilized.

Instruments for this purpose can include two elongated jaw members whichare respectively used to capture or clamp tissue. Typically, one of thejaw members carries a staple cartridge which houses a plurality ofstaples arranged in at least two lateral rows while the other jaw memberhas an anvil that defines a surface for forming the staple legs as thestaples are driven from the staple cartridge. Generally, the staplingoperation is effected by cam members that travel longitudinally throughthe staple cartridge, with the cam members acting upon staple pushers tosequentially eject the staples from the staple cartridge. A knife cantravel between the staple rows to longitudinally cut and/or open thestapled tissue between the rows of staples. Such instruments aredisclosed, for example, in U.S. Pat. Nos. 3,079,606 and 3,490,675.

A later stapler disclosed in U.S. Pat. No. 3,499,591 also applies adouble row of staples on each side of the incision. This patentdiscloses a surgical stapler that has a disposable loading unit in whicha cam member moves through an elongate guide path between two sets ofstaggered staple carrying grooves. Staple drive members are locatedwithin the grooves and are positioned in such a manner so as to becontacted by the longitudinally moving cam member to effect ejection ofthe staples from the staple cartridge of the disposable loading unit.Other examples of such staplers are disclosed in U.S. Pat. Nos.4,429,695 and 5,065,929.

Each of the instruments described above is designed for use inconventional surgical procedures wherein surgeons have direct manualaccess to the operative site. However, in endoscopic or laparoscopicprocedures, surgery is performed through a small incision or through anarrow cannula inserted through small entrance wounds in the skin. Inorder to address the specific needs of endoscopic and/or laparoscopicsurgical procedures, endoscopic surgical stapling devices have beendeveloped and are disclosed in, for example, U.S. Pat. No. 5,040,715(Green, et al.); U.S. Pat. No. 5,307,976 (Olson, et al.); U.S. Pat. No.5,312,023 (Green, et al.); U.S. Pat. No. 5,318,221 (Green, et al.); U.S.Pat. No. 5,326,013 (Green, et al.); U.S. Pat. No. 5,332,142 (Robinson,et al.); and U.S. Pat. No. 6,241,139 (Milliman et al.), the entirecontents of each of which are incorporated herein by reference.

Tyco Healthcare Group, LP, the assignee of the present application, hasmanufactured and marketed endoscopic stapling instruments, such as theMultifire ENDO GIA™. 30 and Multifire ENDO GIA™. 60 instruments, for anumber of years. These instruments include a surgical stapling apparatusand a DLU. Typically, the DLU is attached to the apparatus immediatelyprior to surgery. After use, the DLU can be removed from the apparatusand a new DLU can be fastened to the apparatus to perform additionalstapling and/or cutting operations. These instruments have providedsignificant clinical benefits. Nonetheless, improvements to theseinstruments are still possible.

It would be desirable to provide a surgical buttress selectivelyconnected to at least one of the tissue contacting surfaces of thecartridge half-section and the anvil half-section of the surgicalstapling apparatus.

It would also be desirable to provide a system for removing the surgicalbuttress from the tissue contacting surface of the cartridgehalf-section and/or the tissue contacting surface of the anvilhalf-section during a firing of the surgical stapling apparatus.

Accordingly, it is an object of this disclosure to meet theaforementioned desires.

SUMMARY

In accordance with the present disclosure a surgical stapling apparatusis provided including a housing; a handle supported by the housing; anelongated body extending distally from the housing and having a distalend adapted to releasably engage a loading unit; and a loading unitsupportable on a distal end of the housing. The loading unit includes atool assembly having a cartridge assembly configured and adapted toreleasably support a staple cartridge having a plurality of surgicalfasteners therein, and an anvil assembly movably secured in relation tothe cartridge assembly, wherein the anvil assembly is configured andadapted to support an anvil plate and, wherein each of the anvil plateand the staple cartridge define an elongate longitudinal slot. Theloading unit further includes a surgical buttress releasably secured toa tissue contacting surface of at least one of the anvil plate and thestaple cartridge, wherein each surgical buttress is secured to the atleast one of the anvil assembly and the cartridge assembly by at leastone anchor. The loading unit still further includes a drive assemblyslidably supported in the tool assembly, the drive assembly including aknife blade slidably disposed within each elongate longitudinal slot,wherein movement of the drive assembly from a proximal position to adistal position results in the knife blade thereof cutting the at leastone anchor and freeing each surgical buttress from the respective atleast one anvil assembly and cartridge assembly.

The anvil assembly may include a proximal suture securing the surgicalbuttress thereto and/or a distal anchor securing the surgical buttressthereto. The cartridge assembly may include a proximal anchor securingthe surgical buttress thereto and/or a distal anchor securing thesurgical buttress thereto. Each anchor of the anvil assembly and thecartridge assembly may extend across the respective longitudinal slot ofthe anvil plate and the staple cartridge.

The anvil assembly may include a knife blade slidably or rotatablysupported therein and defining a knife edge. The knife blade of theanvil assembly may cut at least one of the proximal and distal anchorsof the anvil assembly upon actuation thereof. The knife blade of theanvil assembly may have a first position located substantially proximalof the distal anchor of the anvil assembly and a second position locatedsubstantially distal of the distal anchor of the anvil assembly, therebycutting the distal anchor of the anvil assembly. The drive assembly maymove the knife blade of the anvil assembly from the first position tothe second position upon distal actuation of the drive assembly.

The cartridge assembly may include a knife blade slidably or rotatablysupported therein and defining a knife edge, wherein the knife blade ofthe cartridge assembly cuts at least one of the proximal and distalanchors of the cartridge assembly upon actuation thereof. The knifeblade of the cartridge assembly may have a first position locatedsubstantially proximal of the distal anchor of the cartridge assemblyand a second position located substantially distal of the distal anchorof the cartridge assembly, thereby cutting the distal anchor of thecartridge assembly. The drive assembly may move the knife blade of thecartridge assembly from the first position to the second position upondistal actuation of the drive assembly.

According to another aspect of the present disclosure, a loading unitfor use with a surgical stapling apparatus is provided. The loading unitincludes a tool assembly having a cartridge assembly configured andadapted to releasably support a staple cartridge having a plurality ofsurgical fasteners therein, and an anvil assembly movably secured inrelation to the cartridge assembly, wherein the anvil assembly isconfigured and adapted to support an anvil plate and, wherein each ofthe anvil plate and the staple cartridge define an elongate longitudinalslot. The loading unit also includes a surgical buttress releasablysecured to a tissue contacting surface of at least one of the anvilplate and the staple cartridge, wherein each surgical buttress issecured to the at least one of the anvil assembly and the cartridgeassembly by at least one anchor. The loading unit further includes adrive assembly slidably supported in the tool assembly, the driveassembly including a knife blade slidably disposed within each elongatelongitudinal slot, wherein movement of the drive assembly from aproximal position to a distal position results in the knife bladethereof cutting the at least one anchor and freeing each surgicalbuttress from the respective at least one anvil assembly and cartridgeassembly.

According to yet another aspect of the present disclosure, a loadingunit for selective use with a surgical stapling apparatus is provided.The loading unit includes a tool assembly having a cartridge assemblyconfigured and adapted to releasably support a staple cartridge having aplurality of surgical fasteners therein, and an anvil assembly movablysecured in relation to the cartridge assembly, wherein the anvilassembly is configured and adapted to support an anvil plate and,wherein each of the anvil plate and the staple cartridge define anelongate longitudinal slot. The loading unit further includes a surgicalbuttress releasably secured to a tissue contacting surface of each ofthe anvil plate and the staple cartridge; and anchors securing thesurgical buttress to each of the anvil plate and the staple cartridge,wherein an anchor is located near a proximal end and a distal end ofeach of the anvil assembly and the cartridge assembly. The loading unitalso includes a knife blade operatively disposed in the anvil assembly,wherein the knife blade of the anvil assembly has a first positionlocated proximal of a distal anchor of the anvil assembly and a secondposition located distal of the distal anchor of the anvil assembly,thereby cutting the distal anchor of the anvil assembly. The loadingunit still further includes a knife blade operatively disposed in thecartridge assembly, wherein the knife blade of the cartridge assemblyhas a first position located proximal of a distal anchor of thecartridge assembly and a second position located distal of the distalanchor of the cartridge assembly, thereby cutting the distal anchor ofthe cartridge assembly. The loading unit also includes a drive assemblyslidably supported in the tool assembly, the drive assembly including aknife blade slidably disposed within each elongate longitudinal slot,wherein movement of the drive assembly from a proximal position to adistal position results in the knife blade thereof cutting a proximalanchor of each of the anvil assembly and the cartridge assembly andfreeing a proximal end of each surgical buttress from the respective atleast one anvil assembly and cartridge assembly, and wherein movement ofthe drive assembly from the proximal position to the distal positionmoves the knife blade of the anvil assembly and the knife blade of thecartridge assembly from their respective first positions to theirrespective second positions, thereby cutting a respective distal anchorof the anvil assembly and the cartridge assembly and freeing a distalend of each surgical buttress from the respective at least one anvilassembly and cartridge assembly.

According to a further aspect of the present disclosure, a surgicalstapling apparatus is provided. The surgical stapling apparatus includesa cartridge assembly defining a tissue contacting surface; an anvilassembly defining a tissue contacting surface; and a surgical buttressreleasably secured to at least one of the tissue contacting surface ofthe cartridge assembly and the tissue contacting surface of the anvilassembly by at least one anchor.

An anchor may be placed near at least one of a proximal end and a distalend of each surgical buttress. Each anchor may extend transverse to alongitudinal axis of a respective one of the cartridge assembly and theanvil assembly.

The anchor may be selected from the group consisting of sutures,threads, tethers, straps, bands, lines, wires, cables, tacks, anchors,and fasteners.

At least a proximal anchor may extend across a respective longitudinalknife slot formed in each of the cartridge assembly and the anvilassembly and/or at least a distal anchor may extend across a respectivelongitudinal knife slot formed in each of the cartridge assembly and theanvil assembly.

The anchor may release a respective surgical buttress upon firing of thesurgical stapling apparatus. Each anchor may be severed to release thesurgical buttress upon a firing of the surgical stapling apparatus.

The surgical stapling apparatus may include a knife blade configured anddimensioned for slidable reciprocation through a respective longitudinalknife slot formed in each of the cartridge assembly and the anvilassembly, wherein the knife blade severs an anchor upon distaladvancement thereof.

The surgical stapling apparatus may further include a drive assemblyslidably supported for axial displacement along the cartridge assemblyand the anvil assembly, wherein movement of the drive assembly from aproximal position to a distal position results in the separation of thesurgical buttress from a respective one of the cartridge assembly andthe anvil assembly.

An anchor may be placed near at least one of a proximal end and a distalend of each surgical buttress. The drive assembly may either directlycut each anchor or may cause each anchor to be cut in order to releasethe surgical buttress from the respective cartridge assembly and anvilassembly.

Additional advantages will become apparent from the description whichfollows, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be further described with reference to theaccompanying drawings, wherein like reference numerals refer to likeparts in the several views, and wherein:

FIG. 1 is a perspective view of a surgical stapling apparatus accordingto an embodiment of the present disclosure;

FIG. 2 is a top, exploded perspective view of a distal end of a DLU ofthe surgical stapling apparatus of FIG. 1;

FIG. 3 is a top, perspective view of the DLU of FIG. 2, shown in anassembled condition;

FIG. 4 is a top, perspective view of a distal end of the DLU of FIG. 2;

FIG. 5 is a further top, perspective view of the distal end of the DLUof FIGS. 2 and 4, having a top, front cover removed therefrom;

FIG. 6 is a top, perspective view of a proximal end of the DLU of FIGS.2-5;

FIG. 7 is a side, elevational view of the distal end of the DLU of FIGS.2-6;

FIG. 8 is a top, plan view of the distal end of the DLU of FIGS. 2-7;

FIG. 9 is a bottom, perspective view of a distal end of an anvilhalf-section of the DLU of FIGS. 2-8, illustrating a knife assemblyassociated therewith;

FIG. 10 is a bottom, perspective view of a proximal end of the anvilhalf-section of FIG. 9, illustrating the knife assembly associatedtherewith;

FIG. 11 is a top, perspective view of a distal end of a cartridgehalf-section of the DLU of FIG. 2;

FIG. 12 is a side, elevational view of the distal end of the cartridgehalf-section of the DLU of FIGS. 2 and 11

FIG. 13 is a bottom, perspective view of the distal end of the cartridgehalf-section of the DLU of FIGS. 2, 11 and 12;

FIG. 14 is a further bottom, perspective view of the distal end of thecartridge half-section of the DLU of FIGS. 2 and 11-13;

FIG. 15 is an enlarged, perspective view of the indicated area of detailof FIG. 13;

FIG. 16 is a bottom, enlarged, perspective view of the distal end of thecartridge half-section of the DLU of FIGS. 2 and 11-15;

FIG. 17 is a bottom, plan view of the distal end of the cartridgehalf-section of the DLU of FIGS. 2 and 11-16;

FIG. 18 is a longitudinal, cross-sectional view of the distal end of thecartridge half-section of the DLU of FIGS. 2 and 11-17;

FIG. 19 is a bottom, perspective view of the distal end of the cartridgehalf-section of the DLU of FIGS. 2 and 11-18;

FIG. 20 is an exploded, perspective view of a distal end of a DLU of thesurgical stapling apparatus of FIG. 1, according to another embodimentof the present disclosure;

FIG. 21 is perspective view of the distal end of the DLU of FIG. 20;

FIG. 22 is a top, perspective view of a distal end of an anvilhalf-section of the DLU of FIGS. 20 and 21;

FIG. 23 is a bottom, perspective view of the distal end of the anvilhalf-section of FIG. 22, having an anvil plate removed therefrom;

FIG. 24 is a top, perspective view of a proximal end of the anvilhalf-section of the DLU of FIGS. 20 and 21;

FIG. 25 is a bottom, perspective view of the proximal end of the anvilhalf-section of FIG. 24;

FIG. 26 is a top, perspective view of a cartridge half-section of theDLU of FIGS. 20 and 21;

FIG. 27 is a top, perspective view of a distal end of the cartridgehalf-section of FIG. 26;

FIG. 28 is a top, perspective view of the distal end of the cartridgehalf-section of FIG. 27, having a blade stop insert removed therefrom;

FIG. 29 is a side elevational view of the distal end of the cartridgehalf-section of FIG. 28;

FIG. 30 is a top, perspective view of the blade stop insert of thecartridge half-section of FIGS. 26 and 27;

FIG. 31 is a bottom, perspective view of the blade stop insert of thecartridge half-section of FIGS. 26 and 27;

FIG. 32 is a perspective view of the distal end of the cartridgehalf-section of FIGS. 26 and 27, having a distal nose cap removedtherefrom;

FIG. 33 is a perspective view of a distal end of a cartridge assembly,according to another embodiment of the present disclosure, of a DLU of asurgical stapling apparatus;

FIG. 34 is a perspective view of a distal end of an anvil assembly,according to another embodiment of the present disclosure, of a DLU of asurgical stapling apparatus;

FIG. 35 is a top, plan view of the distal end of the anvil assembly ofFIG. 34, illustrating a knife blade thereof in a first position;

FIG. 36 is a top, plan view of the distal end of the anvil assembly ofFIGS. 34 and 35, illustrating the knife blade thereof in a secondposition;

FIG. 37 is a perspective view of a distal end of a cartridge assembly,according to another embodiment of the present disclosure, of a DLU of asurgical stapling apparatus;

FIG. 38 is a top, plan view of the distal end of the cartridge assemblyof FIG. 37, illustrating a knife blade thereof in a first position;

FIG. 39 is a top, plan view of the distal end of the cartridge assemblyof FIGS. 37 and 38, illustrating the knife blade thereof in a secondposition;

FIG. 40 is a perspective view of a distal end of an anvil assembly,according to yet another embodiment of the present disclosure, of a DLUof a surgical stapling apparatus;

FIG. 41 is a top, plan view of the distal end of the anvil assembly ofFIG. 40, illustrating a knife blade thereof in a first position;

FIG. 42 is a top, plan view of the distal end of the anvil assembly ofFIGS. 40 and 41, illustrating the knife blade thereof in a secondposition;

FIG. 43 is a perspective view of a distal end of a cartridge assembly,according to yet another embodiment of the present disclosure, of a DLUof a surgical stapling apparatus;

FIG. 44 is a top, plan view of the distal end of the cartridge assemblyof FIG. 43, illustrating a knife blade thereof in a first position;

FIG. 45 is a top, plan view of the distal end of the cartridge assemblyof FIGS. 43 and 44, illustrating the knife blade thereof in a secondposition;

FIG. 46 is a schematic, perspective view of a distal end of an anvilassembly, according to still another embodiment of the presentdisclosure, of a DLU of a surgical stapling apparatus;

FIG. 47 is an exploded, perspective view of a DLU of the surgicalstapling apparatus of FIG. 1, according to another embodiment of thepresent disclosure;

FIG. 48 is a side elevational view of the DLU of FIG. 47;

FIG. 49. is an exploded perspective view of the DLU of FIGS. 47 and 48;

FIG. 50 is an enlarged perspective view of an actuation sled of the DLUof FIGS. 47-49;

FIG. 51 is an enlarged perspective view of the DLU of FIGS. 47-49, shownin a closed condition;

FIG. 52 is an enlarged view of the indicated area of detail of FIG. 47;

FIG. 53 is a longitudinal cross-sectional elevation view of the DLU, astaken through 53-53 of FIG. 47;

FIG. 54 is an enlarged view of the indicated area of detail of FIG. 53;

FIG. 55 is an enlarged view of the indicated area of detail of FIG. 53;

FIG. 56 is a perspective view of a cartridge assembly of the DLU ofFIGS. 47-49;

FIG. 57 is an enlarged perspective view of a distal end of the cartridgeassembly of FIG. 56;

FIG. 58 is an enlarged view of the indicated area of detail of FIG. 56;

FIG. 59 is an enlarged view of the indicated area of detail of FIG. 58;

FIG. 60 is a perspective view, with parts separated, of the distal endof the cartridge assembly of FIG. 56;

FIG. 61 is a bottom, perspective view of a knife blade assembly of thecartridge assembly of FIG. 56;

FIG. 62 is a top, perspective view of a knife blade assembly of thecartridge assembly of FIG. 56;

FIG. 63 is a bottom, perspective view of a proximal end of an anvilassembly of the DLU of FIGS. 47-49;

FIG. 64 is a perspective view, with parts separated, of the anvilassembly of FIG. 63;

FIG. 65 is a bottom, perspective view of the anvil assembly of FIGS. 63and 64;

FIG. 66 is a bottom, perspective view of the anvil assembly of FIG. 65,with a buttress removed therefrom;

FIG. 67 is a bottom, perspective view of the anvil assembly of FIG. 65,with a buttress and an anvil plate removed therefrom;

FIG. 68 is a longitudinal cross-sectional elevation view of the DLU, astaken through 53-53 of FIG. 47, illustrating an initial actuation of adrive assembly thereof;

FIG. 69 is an enlarged view of the indicated area of detail of FIG. 68;

FIG. 70 is a longitudinal cross-sectional elevation view of the DLU, astaken through 53-53 of FIG. 47, illustrating a final actuation of thedrive assembly thereof;

FIG. 71 is an enlarged view of the indicated area of detail of FIG. 70;

FIG. 72 is an enlarged distal perspective view of the DLU of FIGS. 70and 71, following an actuation thereof;

FIG. 73 is a schematic, perspective illustration of the actuation sledengaging a knife blade assembly;

FIG. 74 is a top, plan view of the actuation sled engaging a knife bladeassembly; and

FIG. 75 is an enlarged perspective view of a distal end of the cartridgeassembly following a complete actuation of the drive assembly.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed surgical stapling apparatus andDLU will now be described in detail with reference to the drawings, inwhich like reference numerals designate identical or correspondingelements in each of the several views.

In the drawings and in the description that follows, the term“proximal”, as is traditional, will refer to the end of the staplingapparatus which is closest to the operator, while the term “distal” willrefer to the end of the apparatus which is furthest from the operator.

FIG. 1 shows a surgical apparatus, e.g., surgical stapling apparatus,generally referred to as 10. In the interest of brevity, this disclosurewill focus primarily on systems, methods and structures for loading,engaging, coupling or connecting a disposable loading unit (“DLU”) 16 tosurgical stapling apparatus 10. A detailed discussion of the remainingcomponents and method of use of surgical stapling apparatus 10 isdisclosed in U.S. Pat. No. 6,241,139.

Surgical stapling apparatus 10 is an endoscopic apparatus and includes ahandle assembly 12 and an elongated body 14 extending from handleassembly 12. A DLU 16 is releasably secured to the distal end ofelongated body 14. While this disclosure relates to the use of a DLUwith surgical stapling apparatus 10, it is understood and within thescope of the present disclosure that a single use loading unit (SULU) orother end effector and/or tool assembly can equally be used incooperation with surgical stapling apparatus 10.

DLU 16 includes a tool assembly 17 having a cartridge assembly 18housing a plurality of surgical fasteners or staples 84 (see FIG. 2) andan anvil assembly 20 movably secured in relation to cartridge assembly18. As shown herein, DLU 16 is configured to apply six (6) linear rowsof staples, in DLUs measuring from about 30 mm to about 60 mm in length.DLUs for applying any number of rows of staples, having staple pocketsarranged in various patterns and/or DLUs and end effectors having anyother lengths, e.g., 45 mm, are also envisioned. Handle assembly 12includes a stationary handle member 22, a movable handle member 24, anda barrel portion 26.

A rotatable member 28 is mounted on the forward end of barrel portion 26to facilitate rotation of elongated body 14 and attached DLU 16 withrespect to handle assembly 12. An articulation lever 30 is also mountedon the forward end of barrel portion 26 adjacent rotatable member 28 tofacilitate articulation of tool assembly 17. Preferably, a pair of knobs32 are movably positioned along barrel portion 26. Knobs 32 are advanceddistally to approximate or close cartridge and/or anvil assembly 18, 20,and retracted proximally to unapproximate or open cartridge and/or anvilassembly 18, 20.

DLU 16 is desirably selectively removably couplable to elongated body14. DLU 16 includes a housing portion 36 having a proximal end adaptedto releasably engage the distal end of elongated body 14. A mountingassembly 38 is pivotally secured at “P” to the distal end of housingportion 36, and is configured to receive the proximal end of toolassembly 17 such that pivotal movement of tool assembly 17 about an axisat “P”, perpendicular to the longitudinal axis of housing portion 36,effects articulation of tool assembly 17.

With general reference to FIGS. 2-8, DLU 16 includes a mounting assembly40. Mounting assembly 40 includes an upper and a lower mounting portion40 a, 40 b, respectively. A centrally located pivot member 42 extendsfrom each of upper and lower mounting portions 40 a, 40 b.

An axial drive assembly 50 is operatively associated with and slidablydisposed between cartridge and/or anvil assembly 18, 20. With referenceto FIG. 2, axial drive assembly 50 includes an elongated drive beam 52having a distal end 54 and a proximal end 56. Drive beam 52 may beconstructed from a single sheet of material or, preferably, multiplestacked sheets.

Proximal end 56 of drive beam 52 of drive assembly 50 includes a pair ofresilient engagement fingers which are dimensioned and configured tomountingly engage a drive member, e.g., a drive rod or control rod (notshown) when the proximal end of DLU 16 is engaged with elongated body 14of surgical stapling apparatus 10. The control rod functions to impartaxial movement of drive assembly 50 from handle assembly 12.

Distal end 54 of drive beam 52 of drive assembly 50 is configured andadapted to support an I-Beam 60. I-beam 60 includes a central wallportion 62 and an upper and lower rail portion 64 a, 64 b, respectively.A distal edge of central wall portion 62 defines a knife blade or thelike 66.

As seen in FIGS. 2-10, anvil assembly 20 includes an anvil plate 70having a plurality of staple deforming pockets/cavities 70 a (see FIGS.9 and 10) and a cover plate 72 secured to a top surface of anvil plate70, wherein a cavity (not shown) is defined therebetween. The cavitydefined between anvil plate 70 and cover plate 72 is dimensioned toslidably receive upper rail portion 64 a of I-beam 60 therein. Alongitudinal slot 70 b extends through anvil plate 70 to facilitatepassage of central wall portion 62 of I-beam 60 therethrough.

In operation, an upper surface of anvil plate 70 defines a cammingsurface 70 c against which upper rail portion 64 a of I-beam 60 engagesto cam, urge and clamp anvil assembly 20 against the tissue as driveassembly 50 advances I-beam 60 through longitudinal slot 70 b.

With continued reference to FIGS. 2-10, anvil plate 70 defines aproximal pair of recesses 70 d formed near a proximal end of anvil plate70 and disposed, one each, on opposed sides of longitudinal slot 70 b.Anvil plate 70 defines a distal pair of recesses 70 e formed near adistal end of anvil plate 70 and disposed, one each, on opposed sides oflongitudinal slot 70 b. In one embodiment, at least one of the recessesof each of the proximal pair of recesses 70 d and the distal pair ofrecesses 70 e is non-circular, preferably, constricting, so as tofrictionally engage and/or pinch an anchor “S”.

As used herein the term anchor is understood to include and is notlimited to suture, thread, tether, strap, band, line, wire, cable,fastener, tack, anchor or any other material suitable for the intendedpurpose disclosed herein.

Anvil assembly 20 further includes a knife blade 74 defining a distallyoriented knife edge 74 a and being operatively interposed within thecavity defined between anvil plate 70 and cover plate 72. Knife blade 74has an initial or first condition positioned proximal of the distal pairof recesses 70 e and a final or second condition positioned distal ofthe distal pair of recesses 70 e. Knife blade 74 includes an engagingelement 74 b, e.g., a recess, formed in a surface thereof forselectively engaging a complementary engaging element, e.g., nub, (notshown) projecting from a surface of cover plate 72, or a distal cap 76of anvil assembly 20. The engaging elements inter-engage with oneanother to maintain or hold knife blade 74 stationary and in the initialor first condition.

In an embodiment distal cap 76 includes a pair of opposed recesses 76 aformed in opposed side edges thereof which align with the distal pair ofrecesses 70 e formed in anvil plate 70 when cover plate 72 is assembledwith anvil plate 70. Additionally, cover plate 72 defines a pair ofopposed recesses 72 a formed therein which align with the proximal pairof recesses 70 d formed in anvil plate 70 when cover plate 72 isassembled with anvil plate 70.

Anvil assembly 20 further includes a surgical buttress “B”, pledget orthe like operatively secured to a lower surface of anvil plate 70, byanchor “S”, to overlie at least some of anvil pockets 70 a and/or atleast a portion of a length of longitudinal slot 70 b. In particular, ananchor “S” is threaded through a distal portion of the anvil buttress“B” and each of the distal pair of recesses 70 e, and an anchor “S” isthreaded through a proximal portion of anvil buttress “B” and each ofthe proximal pair of recesses 70 d.

In one particular embodiment, a first end of a anchor “S” includes aknot, stop or the like (not shown) sized so as to not pass through onerecess of the proximal pair of recesses 70 d while a second end ofanchor “S” passes through, and transversely across, anvil buttress “B”,at least once, and back through the other recess of the proximal pair ofrecesses 70 d. For example, the second end of anchor “S” may be pinchedor cinched in the other recess of the proximal pair of recesses 70 d soas to anchor the second end of the anchor “S” and secure the anvilbuttress “B” against the lower surface of anvil plate 70. Similarly, ananchor “S” is used to extend transversely across anvil buttress “B” andinto engagement with the distal pair of recesses 70 e.

In operation, as will be discussed in greater detail below, with anvilbuttress “B” secured against the lower surface of anvil plate 70, duringfiring of surgical stapling apparatus 10, as drive assembly 50 isadvanced (i.e., moved from a proximal-most position to a distal-mostposition), knife blade 66 slices through a central section of theproximal anchor “S”, thereby freeing the proximal end of the anvilbuttress “B” from anvil assembly 20. As drive assembly 50 approaches thedistal end of anvil plate 70, upper rail 64 a of I-beam 60 abuts againstand urges knife blade 74 distally. As knife blade 74 is moved distally,from the initial or first condition positioned proximal of the distalpair of recesses 70 e to the final or second condition positioned distalof the distal pair of recesses 70 e, knife edge 74 a thereof slices orcuts through distal anchor “S”, thereby freeing the distal end of theanvil buttress “B” from anvil assembly 20. Knife blade 74 cuts throughthe distal anchor “S” extending through both recesses of the distal pairof recesses 70 e.

As seen in FIGS. 2-8 and 11-19, cartridge assembly 18 includes a carrier80 defining an elongated support channel 80 a. Elongated support channel80 a of carrier 80 is dimensioned and configured to selectively receivea staple cartridge 82 therein. Corresponding tabs and slots formed alongstaple cartridge 82 and carrier 80 function to retain staple cartridge82 within carrier 80. A pair of support struts formed on and extendingfrom staple cartridge 82 are positioned to rest on side walls of carrier80 to further stabilize staple cartridge 82 within support channel 80 aof carrier 80. Staple cartridge 82 includes retention slots 82 a formedtherein for receiving a plurality of fasteners 84 and pushers 86. Aplurality of spaced apart longitudinal slots 82 b extend through staplecartridge 82 to accommodate upstanding cam wedges 90 a of actuation sled90. Actuation sled 90 includes a central upstanding wedge or wall 90 b.Central wall 90 b defines a distal notch or shoulder 90 c formedtherein.

A central longitudinal slot 82 c is formed in and extends along thelength of staple cartridge 82 to facilitate passage of central wallportion 62 of I-beam 60 therethrough. During operation of surgicalstapler 10, actuation sled 90 translates through longitudinal slots 82 bof staple cartridge 82 to advance cam wedges 90 a into sequentialcontact with pushers 92, to cause pushers 92 to translate verticallywithin retention slots 82 a and urge fasteners 84 (e.g., staples) fromslots 82 a into the staple forming cavities 70 a of anvil plate 70 ofanvil assembly 20.

With continued reference to FIGS. 2 and 11-19, staple cartridge 82defines a proximal pair of recesses 82 e formed near a proximal endthereof and disposed, one each, on opposed sides of longitudinal slot 82c. Staple cartridge 82 further defines a distal pair of recesses 82 fformed near a distal end thereof and disposed, one each, on opposedsides of longitudinal slot 82 c. In one embodiment, at least one of therecesses of each of the proximal pair of recesses 82 e and the distalpair of recesses 82 f is non-circular, preferably, constricting, so asto frictionally engage and/or pinch an anchor “S”.

Cartridge assembly 18 further includes a knife blade 94 defining adistally oriented knife edge 94 a (see FIGS. 12-17 and 19) and beingoperatively disposed within a cavity 82 d (see FIGS. 16, 17 and 19)defined near a distal end of staple cartridge 82. Knife blade 94 mayinclude a right side and a left side knife edge 94 a. Knife blade 94 hasan initial or first condition positioned proximal of a distal pair ofrecesses 82 e formed in staple cartridge 82 and a final or secondcondition positioned distal of the distal pair of recesses 82 e.

Knife blade 94 may include an engaging element (not shown) formed in asurface thereof for selectively engaging a complementary engagingelement (not shown) projecting from a surface of staple cartridge 82 ofcartridge assembly 18. The engaging elements inter-engage with oneanother to maintain or hold knife blade 94 stationary and in the initialor first condition.

Cartridge assembly 18 further includes a surgical buttress “B”, pledgetor the like operatively secured to an upper surface of staple cartridge82, by anchors “S”, to overlie at least some of staple pockets 82 aand/or at least a portion of a length of longitudinal slot 82 c. Inparticular, an anchor “S” is threaded through a distal portion of thecartridge buttress “B” and each of the distal pair of recesses 82 f, andan anchor “S” is threaded through a proximal portion of cartridgebuttress “B” and each of the proximal pair of recesses 82 e.

In one particular embodiment, a first end of each anchor “S” includes aknot, stop or the like (not shown) sized so as to not pass through onerecess of the proximal pair of recesses 82 e and a second end of eachanchor “S” passes through, and transversely across, cartridge buttress“B”, at least once, and back through the other recess of the proximalpair of recesses 82 e. For example, the second end of each anchor “S”may be pinched or cinched in the other recess of the proximal pair ofrecesses 82 e so as to anchor the second end of the anchor “S” andsecure the cartridge buttress “B” against the tissue contacting surfaceof staple cartridge 82. Similarly, an anchor “S” is used to extendtransversely across cartridge buttress “B” and into engagement with thedistal pair of recesses 82 f.

In operation, as will be discussed in greater detail below, withcartridge buttress “B” secured against the tissue contacting surface ofstaple cartridge 82, during firing of surgical stapling apparatus 10, asdrive assembly 50 is advanced (i.e., moved from a proximal-most positionto a distal-most position), knife blade 66 slices through a centralsection of the proximal anchor “S”, thereby freeing the proximal end ofthe cartridge buttress “B” from cartridge assembly 18. As seen in FIG.18, as drive assembly 50 approaches the distal end of staple cartridge82, shoulder 90 c of central upstanding wedge or wall 90 b of actuationsled 90 abuts against and urges knife blade 94 distally. As knife blade94 is moved distally, from the initial or first condition positionedproximal of the distal pair of recesses 82 f to the final or secondcondition positioned distal of the distal pair of recesses 82 f, knifeedges 94 a thereof slice or cut through distal anchor “S”, therebyfreeing the distal end of the cartridge buttress “B” from cartridgeassembly 18. Knife blade 94 cuts through the distal anchor “S” extendingthrough both recesses of the distal pair of recesses 82 f.

As drive assembly 50 is advanced from a proximal-most position to adistal-most position, knife blade 66 thereof slices or cutslongitudinally through both anvil buttress “B” and cartridge buttress“B”, thereby dividing the buttresses “B” substantially in half.Additionally, as drive assembly 50 is advanced from a proximal-mostposition to a distal-most position, upstanding cam wedges 90 a ofactuation sled 90 actuates pushers 92, to cause pushers 92 to translatevertically within retention slots 82 a and urge fasteners 84 from slots82 a. As fasteners 84 (e.g., staples) are urged from slots 82 a ofstaple cartridge 82, legs of fasteners 84 penetrate and pass throughboth anvil buttress “B” and cartridge buttress “B”, through any tissue(not shown) interposed between anvil buttress “B” and cartridge buttress“B”, and are formed against or within staple forming cavities 70 a ofanvil plate 70 of anvil assembly 20.

According to the present disclosure, anvil buttress “B” and/or cartridgebuttress “B” is pre-loaded (i.e., from the manufacturer) onto anvilassembly 20 or cartridge assembly 18, respectively, of DLU 17.Additional or replacement buttresses “B” for anvil assembly 20 and/orcartridge assembly 18 may be secured to either anvil assembly 20 orcartridge assembly 18 as needed or desired.

In operation, with DLU 17 coupled to a distal end of elongated body 14of surgical stapling apparatus 10, and with anvil buttress “B” andcartridge buttress “B” pre-loaded onto anvil assembly 20 and cartridgeassembly 18, respectively, surgical stapling apparatus 10 is used inaccordance with methods known by those skilled in the art. Once anvilassembly 20 and cartridge assembly 18 are clamped onto tissue, surgicalstapling apparatus 10 is fired. In firing surgical stapling apparatus10, drive assembly 50 is advanced from a proximal-most position to adistal-most position. In so doing, knife blade 66 of drive assembly 50substantially simultaneously slices or cuts through a central section ofthe proximal anchor “S” of anvil assembly 20 and cartridge assembly 18,thereby respectively freeing the proximal end of anvil buttress “B” andcartridge buttress “B” therefrom.

As drive assembly 50 approaches the distal-most position, upper rail 64a of I-beam 60 abuts against and urges knife blade 74 distally while,substantially simultaneously or concomitantly therewith, shoulder 90 cof central upstanding wedge or wall 90 b of actuation sled 90 abutsagainst and urges knife blade 94 distally. As knife blade 74 is moveddistally, from the initial position to the final position, knife edge 74a thereof slices or cuts through distal anchor “S” of anvil assembly 20,thereby freeing the distal end of the anvil buttress “B” from anvilassembly 20. As knife blade 94 is moved distally, from the initialposition to the final position, knife edges 94 a thereof slice or cutthrough distal anchor “S” of cartridge assembly 18, thereby freeing thedistal end of the cartridge buttress “B” from cartridge assembly 18.

Also, knife blade 66 of drive assembly 50 substantially simultaneouslyslices or cuts longitudinally through both anvil buttress “B” andcartridge buttress “B”, thereby dividing the buttresses “B”substantially in half.

Turning now to FIGS. 20-32, a DLU according to another embodiment of thepresent disclosure, for surgical stapling apparatus 10, is generallydesignated as 116. DLU 116 is substantially similar to DLU 16 and willonly be discussed in detail herein to the extent necessary to identifydifferences in construction and operation.

As seen in FIGS. 20-25, anvil assembly 20 of DLU 116 defines a proximalpair of recesses 70 d formed near a proximal end of anvil plate 70 anddisposed, one each, on opposed sides of longitudinal slot 70 b; and adistal pair of recesses 70 e formed near a distal end of anvil plate 70and disposed, one each, on opposed sides of longitudinal slot 70 b. Asbest seen in FIGS. 22, 24 and 25, at least one recess of each of theproximal pair of recesses 70 d and the distal pair of recesses 70 e isin the form of a notch having a constricting configuration so as tofrictionally cinch, receive and secure a suture, thread or the liketherein.

As seen in FIG. 23, knife blade 74 includes an orientation member 74 c,in the form of a fin or tab, extending from an underside thereof andconfigured and adapted for slidable engagement in longitudinal slot 70 bof anvil plate 70. Orientation member 74 c functions to help maintain aproper or desired orientation of knife blade 74. For example,orientation member 74 c of knife blade 74 may aid in maintaining knifeedge 74 a at a substantially orthogonal orientation with respect tolongitudinal slot 70 b.

As seen in FIGS. 20, 21 and 26-32, staple cartridge 82 of cartridgeassembly 18 of DLU 116 defines a proximal pair of recesses 82 e formednear a proximal end thereof and disposed, one each, on opposed sides oflongitudinal slot 82 c; and a distal pair of recesses 82 f formed near adistal end thereof and disposed, one each, on opposed sides oflongitudinal slot 82 c.

In an embodiment, as seen in FIGS. 20 and 26, it is contemplated thatstaple cartridge 82 may include at least one post extending from anupper surface thereof, and the surgical buttress “B” that is to overliestaple cartridge 82 may include a respective complementary apertureformed therein. In this manner, when surgical buttress “B” is placed onstaple cartridge 82, the aperture(s) thereof and the post(s) of staplecartridge 82 cooperate with one another to substantially orient andalign the surgical buttress “B” over staple cartridge 82.

Staple cartridge 82 defines a distal recess 82 g formed therein forselectively receiving a knife blade insert 83 therein. As seen in FIGS.20, 21 and 26-32, distal recess 82 g of staple cartridge 82 defines aplane that is substantially parallel to a tissue contacting surfacethereof and includes an extension that is substantially aligned withlongitudinal slot 82 c.

As seen in FIG. 31, knife blade insert 83 includes a projection 83 a, inthe form of a nub or the like, for snap-fit engaging a complementaryreceiving structure 74 a (see FIG. 20) formed in knife blade 74 ofcartridge assembly 18 (see FIG. 2). While a knife blade insert 83 havinga projection 83 a is shown, it is envisioned that knife blade insert 83may include a recess or depression formed therein that is configured andadapted for snap-fit engagement with a complementary projectionextending from knife blade 74.

As seen in FIG. 32, knife blade insert 83 functions to maintain knifeblade 74 in the first condition, i.e., located proximal of the distalpair of recesses 82 f of staple cartridge 82, until actuated by driveassembly 50.

Turning now to FIG. 33, a distal end of a cartridge assembly 18, inaccordance with another embodiment of the present disclosure, isgenerally designated as 118. Cartridge assembly 118 is substantiallysimilar to cartridge assembly 18 and will only be discussed in detailherein to the extent necessary to identify differences in constructionand operation.

As best seen in FIGS. 22, 24 and 25, at least one recess of each of theproximal pair of recesses 70 d and the distal pair of recesses 70 e isin the form of a notch having a constricting configuration so as tofrictionally cinch, receive and secure a suture, thread or the liketherein. As seen in FIG. 33, cartridge assembly 18 includes a knifeblade 194 operatively secured in a distal end of carrier 80 or staplecartridge 82. If knife blade 194 is supported in staple cartridge 82,knife blade 194 is replaced when staple cartridge 82 is replaced.

Knife blade 194 includes an arm 194 a having a distal end secured near adistal end of carrier 80 or staple cartridge 82, and a proximal endextending substantially toward handle assembly 12 of surgical staplingapparatus 10. Knife blade 194 includes a knife edge 194 b extending fromproximal end of arm 194 a in a direction substantially parallel withlongitudinal slot 82 c of staple cartridge 82. Knife edge 194 b of knifeblade 194 is substantially aligned between the distal pair of recesses82 f of staple cartridge 82, such that knife edge 194 b is in juxtaposedalignment with an anchor “S” extending between the distal pair ofrecesses 82 f of staple cartridge 82. Arm 194 a of knife blade 194 hasan initial condition wherein knife edge 194 b is spaced away from anchor“S” extending between the distal pair of recesses 82 f of staplecartridge 82.

In operation, as drive assembly 50 is advanced distally, actuation sled90 (e.g., central upstanding wedge 90 b) engages against the proximalend of arm 194 a of knife blade 194 thereby biasing and camming theproximal end of arm 194 a of knife blade 194 towards anchor “S”extending between the distal pair of recesses 82 f of staple cartridge82 such that knife edge 194 b thereof severs or otherwise cuts throughanchor “S” to free surgical buttress “B” from staple cartridge 82.

Knife edge 194 b is retracted into staple cartridge 82 as a result ofthe spring force created by arm 194 a in returning to the un-biased orinitial condition. Alternatively, as seen in FIG. 33, a biasing member195, in the form of a compression spring or the like, may be interposedbetween or operatively associated with carrier 80 and actuation sled 90.In this manner, upon a completion of a firing stroke, actuation sled 90compresses biasing member 195, and upon a removal of the force requiredto complete the firing stroke, biasing member 195 extends and thus urgesactuation sled 90 in a proximal direction thereby allowing knife edge194 b to retract into staple cartridge 82.

Exemplary surgical buttresses “B” for use with the surgical staplingdevices disclosed herein are shown and described in commonly assignedU.S. Pat. Nos. 5,542,594; 5,908,427; 5,964,774; and 6,045,560, andcommonly assigned U.S. Application Serial Nos. 2006/0085034, filed onApr. 20, 2006; and 2006/0135992, filed on Jun. 22, 2006, the entirecontents of each of which is incorporated herein by reference.

As seen throughout the figures, and in particular FIGS. 2, 9-11, 13, 14,20 and 26, each surgical buttress “B” may be provided with a pair ofproximal and/or a pair of distal, spaced apart holes formed therein,wherein the proximal and/or distal holes of the surgical buttress “B”align with and/or are in juxtaposed relation to respective proximaland/or distal recesses of the anvil plate and/or staple cartridge. Theholes of the surgical buttress “B” allow for more efficient and easierattachment of surgical buttress “B” to the anvil plate and/or staplecartridge by anchors “S”.

Turning now to FIGS. 34-36, an anvil assembly according to anotherembodiment of the present disclosure, for use in a DLU of a surgicalstapling apparatus, is generally designated as 220. Anvil assembly 220is substantially similar to anvil assemblies 20 and thus will only bediscussed herein to the extent necessary to identify differences inconstruction and operation thereof.

As seen in FIGS. 34-36, anvil assembly 220 includes a knife blade 274pivotally secured thereto, in particular, near a distal end thereof.Knife blade 274 is positioned so as to rotate about a pivot point tosever anchor “S” as drive assembly 50 (see FIG. 2) is advanced to adistal-most position in anvil assembly 220.

In particular, with continued reference to FIGS. 34-36, anvil assembly220 includes a pivot point 276 b formed in distal cap 276, in coverplate 272 and/or in anvil plate 270 for pivotally engaging or supportingknife blade 274. Knife blade 274 includes a lobe 274 a defining a pivotwindow 274 b configured and dimensioned to pivotally engage pivot point276 b. Pivot point 276 b and pivot window 274 b define a pivot axis “Y”that is spaced a distance from a longitudinal axis “X” of longitudinalslot 270 b of anvil plate 270.

Knife blade 274 defines a camming edge 274 c extending acrosslongitudinal slot 270 b of anvil plate 270, and a knife edge 274 dextending transverse to camming edge 274 c. Knife blade 274 isconfigured and dimensioned such that a portion of camming edge 274 cand/or a portion of knife edge 274 d extend across anchor “S”.

As seen in FIGS. 34 and 35, knife blade 274 has a first position inwhich knife edge 274 d does not extend across recesses 270 e and is outof engagement with anchor “S”. In particular, when in the firstposition, knife edge 274 d of knife blade 274 includes a portionextending proximally of recesses 270 e and a portion extending distallyof recesses 270 e. Additionally, when in the first position, knife edge274 d of knife blade 274 is disposed between recesses 270 e. Also, whenin the first position, camming edge 274 c of knife blade 274 includes atleast a portion extending proximally of recesses 270 e.

As seen in FIG. 36, knife blade 274 has a second position in which knifeedge 274 d extends across a recess 270 e and is in engagement withanchor “S”. In particular, when in the second position, knife edge 274 dof knife blade 274 includes a portion extending or disposed beyondrecess 270 e.

In operation, during firing of surgical stapling apparatus 10, as driveassembly 50 (see FIG. 2) is advanced (i.e., moved from a proximal-mostposition to a distal-most position), drive assembly 50 causes knifeblade 274 to slice through anchor “S”, thereby freeing the distal end ofthe anvil buttress (see FIG. 2). In particular, with knife blade 274 inthe first position, as seen in FIG. 35, as drive assembly 50 is advanceddistally, drive assembly 50 contacts or engages camming edge 274 c ofknife blade 274, as indicated by arrow “A”. As drive assembly 50 isfurther advanced distally, drive assembly 50 creates a moment aroundpivot point 276 b causing knife blade 274 to rotate thereabout, asindicated by arrow “B”. In so doing, as seen in FIG. 36, knife edge 274d of knife blade 274 is advanced or rotated through anchor “S” thussevering anchor “S” and freeing the distal end of the anvil buttress(see FIG. 2).

Turning now to FIGS. 37-39, a cartridge assembly according to anotherembodiment of the present disclosure, for use in a DLU of a surgicalstapling apparatus, is generally designated as 218. Cartridge assembly218 is substantially similar to cartridge assemblies 18 and thus willonly be discussed herein to the extent necessary to identify differencesin construction and operation thereof.

As seen in FIGS. 37-39, cartridge assembly 218 includes a knife blade294 pivotally secured thereto, in particular, near a distal end thereof.Knife blade 294 is positioned so as to rotate about a pivot point tosever anchor “S” as drive assembly 50 (see FIG. 2) is advanced to adistal-most position in cartridge assembly 218.

In particular, with continued reference to FIGS. 37-39, cartridgeassembly 218 includes a pivot point 283 a formed in knife blade insert283 and/or staple cartridge 282 for pivotally engaging or supportingknife blade 294. Knife blade 294 includes a lobe 294 a defining a pivotwindow 294 b configured and dimensioned to pivotally engage pivot point283 a. Pivot point 283 a and pivot window 294 b define a pivot axis “Y”that is spaced a distance from a longitudinal axis “X” of longitudinalslot 282 c of staple cartridge 282.

Knife blade 294 defines a back or camming edge 294 c extending acrosslongitudinal slot 282 c of staple cartridge 282, and a knife edge 294 dextending parallel to camming edge 294 c. Knife blade 294 is configuredand dimensioned such that camming edge 294 c and knife edge 294 d arelocated proximal of anchor “S”.

As seen in FIGS. 37 and 38, knife blade 294 has a first position inwhich knife edge 294 d does not extend across recesses 282 f and is outof engagement with anchor “5”. In particular, when in the firstposition, knife edge 294 d of knife blade 294 is located proximal ofrecess 282 f.

As seen in FIG. 39, knife blade 294 has a second position in which knifeedge 294 d extends across a recess 282 f and is in engagement withanchor “S”. In particular, when in the second position, knife edge 294 dof knife blade 294 includes a portion extending or disposed beyondrecess 282 f.

In operation, during firing of surgical stapling apparatus 10, as driveassembly 50 (see FIG. 2) is advanced (i.e., moved from a proximal-mostposition to a distal-most position), drive assembly 50 causes knifeblade 294 to slice through anchor “S”, thereby freeing the distal end ofthe cartridge buttress “B”. In particular, with knife blade 294 in thefirst position, as seen in FIG. 38, as drive assembly 50 is advanceddistally, drive assembly 50 contacts or engages camming edge 294 c ofknife blade 294, as indicated by arrow “A”. As drive assembly 50 isfurther advanced distally, drive assembly 50 creates a moment aroundpivot point 283 a causing knife blade 294 to rotate thereabout, asindicated by arrow “B”. In so doing, as seen in FIG. 39, knife edge 294d of knife blade 294 is advanced or rotated through anchor “S” thussevering anchor “S” and freeing the distal end of the cartridge buttress“B”.

Turning now to FIGS. 40-42, an anvil assembly according to yet anotherembodiment of the present disclosure, for use in a DLU of a surgicalstapling apparatus, is generally designated as 320. Anvil assembly 320is substantially similar to anvil assembly 220 and thus will only bediscussed herein to the extent necessary to identify differences inconstruction and operation thereof.

As seen in FIGS. 40-42, anvil assembly 320 includes a knife blade 374pivotally secured thereto, in particular, near a distal end thereof.Knife blade 374 is positioned so as to rotate about a pivot point tosever anchor “S” as drive assembly 50 (see FIG. 2) is advanced to adistal-most position in anvil assembly 320.

In particular, with continued reference to FIGS. 40-42, anvil assembly320 includes a pivot point 376 b formed in distal cap 376, in coverplate (not shown) and/or in anvil plate 370 for pivotally engaging orsupporting knife blade 374. Knife blade 374 includes a lobe 374 adefining a pivot window 374 b configured and dimensioned to pivotallyengage pivot point 376 b. Pivot point 376 b and pivot window 374 bdefine a pivot axis “Y” that is spaced a distance from a longitudinalaxis “X” of longitudinal slot 370 b of anvil plate 370.

Knife blade 374 defines a camming edge 374 c extending acrosslongitudinal slot 370 b of anvil plate 370, and a knife edge 374 dextending transverse to camming edge 374 c. Knife blade 374 isconfigured and dimensioned such that camming edge 374 c is disposedproximally of anchor “S” and a portion of knife edge 374 d extendsacross anchor “S”.

As seen in FIGS. 40 and 41, knife blade 374 has a first position inwhich knife edge 374 d does not extend across recesses 370 e and is outof engagement with anchor “S”. In particular, when in the firstposition, knife edge 374 d of knife blade 374 includes a portionextending proximally of recesses 370 e. Also, when in the firstposition, camming edge 374 c of knife blade 374 is disposed or locatedproximally of recesses 370 e.

As seen in FIG. 42, knife blade 374 has a second position in which knifeedge 374 d extends across a recess 370 e and is in engagement withanchor “S”. In particular, when in the second position, knife edge 374 dof knife blade 374 includes a portion extending or disposed beyondrecess 370 e.

In operation, during firing of surgical stapling apparatus 10, as driveassembly 50 (see FIG. 2) is advanced (i.e., moved from a proximal-mostposition to a distal-most position), drive assembly 50 causes knifeblade 374 to slice through anchor “S”, thereby freeing the distal end ofthe anvil buttress (see FIG. 2). In particular, with knife blade 374 inthe first position, as seen in FIG. 41, as drive assembly 50 is advanceddistally, drive assembly 50 contacts or engages camming edge 374 c ofknife blade 374, as indicated by arrow “A”. As drive assembly 50 isfurther advanced distally, drive assembly 50 creates a moment aroundpivot point 376 b causing knife blade 374 to rotate thereabout, asindicated by arrow “B”. In so doing, as seen in FIG. 42, knife edge 374d of knife blade 374 is advanced or rotated through anchor “S” thussevering anchor “S” and freeing the distal end of the anvil buttress(see FIG. 2).

Turning now to FIGS. 43-45, a cartridge assembly according to anotherembodiment of the present disclosure, for use in a DLU of a surgicalstapling apparatus, is generally designated as 318. Cartridge assembly318 is substantially similar to cartridge assembly 218 and thus willonly be discussed herein to the extent necessary to identify differencesin construction and operation thereof.

As seen in FIGS. 43-45, cartridge assembly 318 includes a knife blade394 pivotally secured thereto, in particular, near a distal end thereof.Knife blade 394 is positioned so as to rotate about a pivot point tosever anchor “S” as drive assembly 50 (see FIG. 2) is advanced to adistal-most position in cartridge assembly 318.

In particular, with continued reference to FIGS. 43-45, cartridgeassembly 318 includes a pivot point 383 a formed in knife blade insert383 and/or staple cartridge 382 for pivotally engaging or supportingknife blade 394. Knife blade 394 includes a lobe 394 a defining a pivotwindow 394 b configured and dimensioned to pivotally engage pivot point383 a. Pivot point 383 a and pivot window 394 b define a pivot axis “Y”that is spaced a distance from a longitudinal axis “X” of longitudinalslot 382 c of staple cartridge 382.

Knife blade 394 defines a back or camming edge 394 c extending acrosslongitudinal slot 382 c of staple cartridge 382, and a knife edge 394 dextending parallel to camming edge 394 c. Knife blade 394 is configuredand dimensioned such that camming edge 394 c and knife edge 394 d arelocated proximal of anchor “S”.

As seen in FIGS. 43 and 44, knife blade 394 has a first position inwhich knife edge 394 d does not extend across recesses 382 f and is outof engagement with anchor “S”. In particular, when in the firstposition, knife edge 394 d of knife blade 394 is located proximal ofrecess 382 f.

As seen in FIG. 45, knife blade 394 has a second position in which knifeedge 394 d extends across a recess 382 f and is in engagement withanchor “S”. In particular, when in the second position, knife edge 394 dof knife blade 394 includes a portion extending or disposed beyondrecess 382 f.

In operation, during firing of surgical stapling apparatus 10, as driveassembly 50 (see FIG. 2) is advanced (i.e., moved from a proximal-mostposition to a distal-most position), drive assembly 50 pushes actuationsled 90 into knife blade 394 causing knife blade 394 to slice throughanchor “S”, thereby freeing the distal end of the cartridge buttress“B”. In particular, with knife blade 394 in the first position, as seenin FIG. 44, as drive assembly 50 is advanced distally, drive assembly 50moved actuation sled 90 into contact or engagement with camming edge 394c of knife blade 394, as indicated by arrow “A”. As drive assembly 50 isfurther advanced distally, actuation sled 90 creates a moment aroundpivot point 383 a causing knife blade 394 to rotate thereabout, asindicated by arrow “B”. In so doing, as seen in FIG. 45, knife edge 394d of knife blade 394 is advanced or rotated through anchor “S” thussevering anchor “S” and freeing the distal end of the cartridge buttress“B”.

Turning now to FIG. 46, an anvil assembly according to yet anotherembodiment of the present disclosure, for use in a DLU of a surgicalstapling apparatus, is generally designated as 420. Anvil assembly 420is substantially similar to anvil assemblies 220 and 320 and thus willonly be discussed herein to the extent necessary to identify differencesin construction and operation thereof.

As seen in FIG. 46, anvil assembly 420 includes a knife blade 474pivotally secured thereto, in particular, near a distal end thereof.Knife blade 474 is positioned so as to rotate about a pivot point tosever anchor “S” as drive assembly 50 (see FIG. 2) is advanced to adistal-most position in anvil assembly 420.

In particular, with continued reference to FIG. 46, anvil assembly 420includes a pivot point 476 b formed in distal cap 476, in the coverplate (not shown) and/or in anvil plate 470 for pivotally engaging orsupporting knife blade 474. Knife blade 474 includes a lobe 474 adefining a pivot window 474 b configured and dimensioned to pivotallyengage pivot point 476 b. Pivot point 476 b and pivot window 474 bdefine a pivot axis “Y” that is spaced a distance from a longitudinalaxis “X” of longitudinal slot 470 b of anvil plate 470.

Knife blade 474 defines a camming edge 474 c extending acrosslongitudinal slot 470 b of anvil plate 470, and a knife edge 474 dextending transverse to camming edge 474 c. Knife blade 474 isconfigured and dimensioned such that camming edge 474 c is disposedproximally of the anchor (not shown) and a portion of knife edge 474 dextends across anchor.

As seen in FIG. 46, knife blade 474 has a first position in which knifeedge 474 d does not extend across recesses 470 e and is out ofengagement with anchor. In particular, when in the first position, knifeedge 474 d of knife blade 474 includes a portion extending proximally ofrecesses 470 e and a portion extending distally of recesses 470 e. Also,when in the first position, camming edge 474 c of knife blade 474 isdisposed or located proximally of recesses 470 e.

Turning now to FIGS. 47-75, an end effector, configured for use orconnection with a handle of an endoscopic surgical stapling apparatus isgenerally designated as 1000. End effector 1000 includes a cartridgeassembly 1200 housing a plurality of surgical fasteners or staples 1228(see FIG. 48) and an anvil assembly 1300 movably secured in relation tocartridge assembly 1200. End effector 1000 measures from about 30 mm toabout 60 mm in length. End effector 1000 may be configured to apply six(6) linear rows of staples.

As seen in FIGS. 47-49, end effector 1000 is configured as a disposableloading unit configured for selective connection with a handle assembly(not shown).

As seen in FIG. 49, end effector 1000 includes an axial drive assembly1150 operatively associated with and slidably disposed between cartridgeassembly 1200 and anvil assembly 1300. Axial drive assembly 1150includes an elongated drive beam 1152 having a distal end 1152 a and aproximal end 1152 b. Drive beam 1152 is constructed from multiplestacked beams.

Proximal end 1152 b of drive beam 1152 is formed as a pair of resilientengagement fingers which are dimensioned and configured to mountinglyengage a drive or control rod (not shown) when the proximal end of endeffector 1000 is connected to the handle assembly.

Distal end 1152 a of drive beam 1152 is configured as an I-beamincluding an upper and lower rail portion 1154 a, 1154 b, respectively,extending transversely therefrom. A distal edge of a central beam ofdrive beam 1152 defines a knife blade 1156.

As seen in FIGS. 49-62, cartridge assembly 1200 includes a carrier 1210defining an elongated support channel 1212. Elongated support channel1212 of carrier 1210 is dimensioned and configured to selectivelyreceive a staple cartridge 1220 therein. Corresponding tabs and slotsformed along staple cartridge 1220 and carrier 1210 function to retainstaple cartridge 1220 within carrier 1210. Staple cartridge 1220includes retention slots 1222 formed therein for receiving a pluralityof surgical staples 1224 and pushers 1226.

As seen in FIGS. 49, 50, 53 and 55, cartridge assembly 1200 furtherincludes an actuation sled 1228 slidably disposed between staplecartridge 1220 and carrier 1210. Actuation sled 1228 includes a centralupstanding wedge or wall 1228 a flanked by a pair of outer cam wedges orwalls 1228 b. Central wall 1228 a defines a distal notch or shoulder1228 c formed therein.

As seen in FIGS. 49 and 60, a central longitudinal slot 1234 is formedin and extends along the length of staple cartridge 1220 to enablepassage of drive beam 1152 therethrough. During operation of thesurgical stapler, actuation sled 1228 translates along staple cartridge1220 and carrier 1210 to advance outer cam wedges 1228 b into sequentialcontact with pushers 1226, to cause pushers 1226 to translate verticallywithin retention slots 1222 and urge staples 1224 from slots 1222 intothe staple forming cavities 1312 of anvil plate 1310 of anvil assembly1300 (see FIG. 66).

With reference to FIGS. 56-59, staple cartridge 1220 defines a proximalpair of recesses 1236 formed near a proximal end thereof and disposed,one each, on opposed sides of longitudinal slot 1234. Staple cartridge1220 further defines a distal pair of recesses 1238 formed near a distalend thereof and disposed, one each, on opposed sides of longitudinalslot 1234. As seen in FIGS. 57-59, at least one recess of each of theproximal pair of recesses 1236 and the distal pair of recesses 1238 isin the form of a slot or notch having a constricting profile so as tofrictionally engage and/or pinch a suture “S”.

As seen in FIGS. 49, 53, 54, 57 and 60-62, cartridge assembly 1200further includes a knife blade 1240 defining a distally oriented knifeedge 1242 and being pivotally supported in staple cartridge 1220. Knifeblade 1240 has an initial or first condition wherein knife edge 1242 ispositioned proximal of one of the distal pair of recesses 1238 and afinal or second condition wherein knife edge 1242 is positioned distalof the one of the distal pair of recesses 1238.

Cartridge assembly 1200 includes a knife blade housing 1246 supported instaple cartridge 1220 at a location associated with the distal pair ofrecesses 1238. As seen in FIG. 61, knife blade housing 1246 includes ahub 1246 a onto which knife blade 1240 is rotatably connected.

As seen in FIGS. 49, 51, 52 and 54-59, cartridge assembly 1200 furtherincludes a surgical cartridge buttress “B1” operatively secured to anupper surface of staple cartridge 1220, by sutures “S”, to overlie atleast some of retention slots 1222 and/or at least a portion of a lengthof longitudinal slot 1234. Surgical cartridge buttress “B1” includes aproximal end portion in the form of tongue “B1 a” having a transversewidth dimension which is less than a transverse width dimension ofsurgical cartridge buttress “B1”, and a distal end portion in the formof tongue “B1 b” having a transverse width dimension which is less thanthe transverse width dimension of surgical cartridge buttress “B1”. Theproximal end portion “B1 a” of surgical cartridge buttress “B1” definesa pair of apertures “B1 c” formed therein for receiving posts 1252 ofstaple cartridge 1220 therein. A first suture “S1” is threaded througheach of the distal pair of recesses 1238 and around/over distal tongue“B1 b” of cartridge buttress “B1” and, and a second suture “S2” isthreaded through each of the proximal pair of recesses 1236 andaround/over proximal tongue “B1 a” of cartridge buttress “B1”.

A first end of each suture “S1, S2” is anchored or fixed in a respectiveone recesses of the proximal and distal pair of recesses 1236, 1238while a second end of each suture “S1, S2” passes transversely acrossrespective distal and proximal tongues “B1 b, B1 a” of cartridgebuttress “B1” and is anchored or fixed in a respective other recess ofthe proximal and distal pair of recesses 1236, 1238.

As seen in FIGS. 49, 56 and 58, staple cartridge 1220 includes a pair ofspaced apart posts 1252 disposed on opposed sides of longitudinal slot1234. Posts 1252 are located distal of and adjacent to proximal suture“S2”. Posts 1252 are received in openings formed in cartridge buttress“B1”. Posts 1252 function to maintain the position of cartridge buttress“B1” relative to staple cartridge 1220 as drive assembly 1150 is moveddistally. Posts 1252 also function to brace proximal sutures “S2” asdrive assembly 1150 is moved distally.

As seen in FIGS. 49, 51-55 and 63-67, anvil assembly 1300 includes ananvil plate 1310 having a plurality of staple deforming pockets/cavities1312 (see FIG. 66) and a cover plate 1320 secured to a top surface ofanvil plate 1310, wherein a cavity 1313 is defined therebetween. Thecavity defined between anvil plate 1310 and cover plate 1320 isdimensioned to slidably receive upper rail portion 1154 a of drive beam1152 therein. A longitudinal slot 1314 extends through anvil plate 1310to facilitate passage of drive beam 1152 therethrough.

In operation, an upper surface of anvil plate 1310 defines a cammingsurface 1310 a against which upper rail portion 1154 a of drive beam1152 engages to cam, urge and clamp anvil assembly 1300 against thetissue as drive assembly 1150 advances drive beam 1152 throughlongitudinal slot 1314.

With continued reference to FIGS. 49, 51, 52 and 63-67, anvil plate 1310defines a proximal pair of recesses 1316 formed near a proximal end ofanvil plate 1310 and disposed, one each, on opposed sides oflongitudinal slot 1314. Anvil plate 1310 defines a distal pair ofrecesses 1318 formed near a distal end of anvil plate 1310 and disposed,one each, on opposed sides of longitudinal slot 1314. At least onerecess of each of the proximal pair of recesses 1316 and the distal pairof recesses 1318 is in the form of a slot or notch having a constrictingprofile so as to frictionally engage and/or pinch a suture “S”.

As seen in FIGS. 49, 51-54 and 64-67, anvil assembly 1300 furtherincludes a knife blade 1330 defining a distally oriented knife edge 1332and being pivotably interposed within the cavity defined between anvilplate 1310 and cover plate 1320. Knife blade 1330 has an initial orfirst condition wherein knife edge 1332 is positioned proximal of one ofthe distal pair of recesses 1318 and a final or second condition whereinknife edge 1332 is positioned distal of the one of the distal pair ofrecesses 1318.

As seen in FIGS. 49, 51-54 and 64-67, anvil assembly 1300 includes aknife blade housing 1336 supported between anvil plate 1310 and coverplate 1320 at a location associated with the distal pair of recesses1318. As seen in FIGS. 64 and 67, knife blade housing 1336 includes ahub 1336 a onto which knife blade 1330 is rotatably connected.

Anvil assembly 1300 further includes a surgical anvil buttress “B2”operatively secured to a lower surface of anvil plate 1310, by sutures“S”, to overlie at least some of anvil pockets 1312 a and/or at least aportion of a length of longitudinal slot 1314. Surgical anvil buttress“B2” includes a proximal end portion in the form of tongue “B2 a” havinga transverse width dimension which is less than a transverse widthdimension of surgical anvil buttress “B2”, and a distal end portion inthe form of tongue “B2 b” having a transverse width dimension which isless than the transverse width dimension of surgical anvil buttress“B2”. A first suture “S3” is threaded through each of the distal pair ofrecesses 1318, and a second suture “S4” is threaded through each of theproximal pair of recesses 1316.

A first end of suture “S3” is anchored or fixed in a recess of thedistal pair of recesses 1318 and a second end of suture “S3” passesaround/over distal tongue “B2 b” of anvil buttress “B2”, transverselythereacross anvil buttress “B2”, so as to be anchored or fixed in theother recess of the distal pair of recesses 1318.

A first end of suture “S4” is anchored or fixed in a recess of theproximal pair of recesses 1316 while a second end of suture “S4” passesaround/over proximal tongue “B2 a” of anvil buttress “B2” and isanchored or fixed in the other recess of the proximal and pair ofrecesses 1316.

As seen in FIGS. 47-49, 51, 63 and 65-67, cover plate 1320 of anvilassembly 1300 includes a pair of walls 1322 extending in a direction ofanvil plate 1310. Walls 1322 are formed near a proximal end of coverplate 1320 and extend from opposed side edges thereof. Walls 1322 areconfigured such that when cartridge assembly 1200 and anvil assembly1300 are in a closed or clamped condition, walls 1322 extends across atissue gap defined therebetween. Walls 1322 function as tissue stops,inhibiting tissue flow in a proximal direction during a clamping orclosing of end effector 1000.

In operation, as seen in FIGS. 68-72, with anvil buttress “B2” securedagainst the lower surface of anvil plate 1310, during firing of thesurgical stapling apparatus, as drive assembly 1150 is advanced (e.g.,moved from a proximal-most position to a distal-most position), knifeblade 1156 slices through a central section of suture “S4”, therebyfreeing the proximal end of anvil buttress “B2” from anvil assembly1300. As drive assembly 1150 approaches the distal end of anvil assembly1300, upper rail portion 1154 a of drive beam 1152 abuts against andurges knife blade 1330 to rotate distally. As knife blade 1330 isrotated distally, knife edge 1332 is rotated from the initial or firstcondition positioned proximal of one of the distal pair of recesses 1318to the final or second condition positioned distal of the one of thedistal pair of recesses 1318. In so doing, knife edge 1332 slices orcuts through suture “S3”, thereby freeing the distal end of the anvilbuttress “B2” from anvil assembly 1300.

Concomitantly therewith, in operation, as seen in FIGS. 68-75, withcartridge buttress “B1” secured against the tissue contacting surface ofstaple cartridge 1220, during firing of the surgical stapling apparatus,as drive assembly 1150 is advanced (e.g., moved from a proximal-mostposition to a distal-most position), knife blade 1156 slices through acentral section of the proximal suture “S2”, thereby freeing theproximal end of the cartridge buttress “B1” from cartridge assembly1200.

As drive assembly 1150 approaches the distal end of staple cartridge1220, shoulder 1228 c of central upstanding wedge or wall 1228 a ofactuation sled 1228 abuts against and urges knife blade 1240 to rotatedistally. As knife blade 1240 is rotated distally, knife edge 1242 isrotated from the initial or first condition positioned proximal of oneof the distal pair of recesses 1238 to the final or second conditionpositioned distal of the one of the distal pair of recesses 1238. In sodoing, knife edge 1242 slices or cuts through distal suture “S1”,thereby freeing the distal end of the cartridge buttress “B1” fromcartridge assembly 1200.

As drive assembly 1150 is advanced from a proximal-most position to adistal-most position, knife blade 1156 thereof slices or cutslongitudinally through both cartridge buttress “B1” and anvil buttress“B”, thereby dividing the buttresses “B1, B2” substantially in half.Additionally, as drive assembly 1150 is advanced from a proximal-mostposition to a distal-most position, upstanding cam wedges 1228 b ofactuation sled 1228 actuates pushers 1226, to cause pushers 1226 totranslate vertically within retention slots 1222 and urge staples 1224from slots 1222. As staples 1224 are urged from slots 1222 of staplecartridge 1220, legs of staples 1224 penetrate and pass through bothcartridge buttress “B1” and anvil buttress “B2”, through any tissue (notshown) interposed between cartridge buttress “B1” and anvil buttress“B2”, and are formed against or within staple deforming pockets 1312 ofanvil plate 1310 of anvil assembly 1300.

Surgical buttresses “B1, B2” are each fabricated from a suitablebiocompatible and bioabsorbable material. Surgical buttresses “B1, B2”are each fabricated from a non-absorbent material which does not retainfluid. Surgical buttresses “B1, B2” are each fabricated from “BIOSYN”made from GLYCOMER 631 (a block copolymer), a synthetic polyestercomposed of glycolide, dioxanone and trimethylene carbonate.

One block of the resulting copolymer contains randomly combined unitsderived from p-dioxanone (1,4-dioxan-2-one) and trimethylene carbonate(1,3-dioxan-2-one). The second block of the copolymer contains randomlycombined units derived from glycolide and p-dioxanone. The resultingpolyester is an ABA triblock terpolymer possessing about 60% glycolide,about 14% dioxanone, and about 26% trimethylene carbonate.

End effector 1000 is shown in FIGS. 47 and 48 as being capable ofarticulation about a pivot point. Cartridge assembly 1200 and anvilassembly 1300 may form a part of a non-articulating SULU.

While the above-described embodiments surgical staplers incorporatingthe use of movable knife blades to sever and release surgical buttressesfrom the tissue contacting surfaces of the anvil assembly and thecartridge assembly have been shown and described in relation toendoscopic surgical staplers, it is envisioned and within the scope ofthe present disclosure that any of the above-embodiments may beincorporated into any type of surgical stapler, including and notlimited to open surgical staplers, such as, for example, linear surgicalstaplers; arcuate or annular surgical staplers; and transverse surgicalstaplers.

It will be understood that various modifications may be made to theembodiments disclosed herein. For example, the stapling apparatus neednot apply staples but rather may apply two part fasteners as is known inthe art. Further, the length of the linear row of staples or fastenersmay be modified to meet the requirements of a particular surgicalprocedure. Thus, the length of a single stroke of the actuation shaftand/or the length of the linear row of staples and/or fasteners within adisposable loading unit may be varied accordingly. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended thereto.

1. (canceled)
 2. A surgical loading unit, comprising: an anvil assembly;a cartridge assembly including: an elongated support channel; a staplecartridge received in the support channel, the staple cartridge defininga longitudinal slot, and retention slots for retaining staples, theanvil assembly and the cartridge assembly together forming a toolassembly and arranged so that the cartridge assembly and anvil assemblyare relatively movable to a position for clamping tissue therebetween; asled having cam wedges for driving staple pushers and ejecting thestaples from the staple cartridge, the sled having a central shoulderthat slides along the longitudinal slot as the sled is moved distallythrough the staple cartridge; a knife blade housing being disposed at adistal end portion of the staple cartridge and defining a pair ofrecesses; and a knife member being attached to the knife blade housingand configured to pivot when contacted by the shoulder of the sled; asurgical buttress configured to be positioned over a tissue-orientedsurface of the staple cartridge so that the surgical buttress overliesthe retention slots; and a first anchor having a portion extending overand across the surgical buttress, wherein the first anchor is configuredto secure the surgical buttress to the staple cartridge, the firstanchor having end portions respectively disposed in the pair of recessesof the knife blade housing.
 3. The surgical loading unit according toclaim 2, wherein the staple cartridge defines a pair of recesses formedtherein for engaging the respective end portions of the first anchor. 4.The surgical loading unit according to claim 3, wherein at least onerecess of the pair of recesses is formed in a longitudinally-extendinglateral side surface of the staple cartridge and frictionally engagesone of the end portions of the first anchor.
 5. The surgical loadingunit according to claim 2, wherein the knife blade housing is fixedrelative to the staple cartridge such that the knife member isconfigured to pivot relative to the knife blade housing.
 6. The surgicalloading unit according to claim 2, further comprising: another surgicalbuttress configured to be positioned over a tissue-oriented surface ofthe anvil assembly; and a second anchor configured to secure the anothersurgical buttress to the anvil assembly.
 7. The surgical loading unitaccording to claim 6, wherein the anvil assembly includes: a knife bladehousing disposed at a distal end portion of the anvil assembly, theknife blade housing of the anvil assembly defining a recess, the secondanchor having an end portion disposed in the recess of the knife bladehousing of the anvil assembly; and a knife member attached to the knifeblade housing of the anvil assembly and configured to move relative tothe knife blade housing of the anvil assembly to sever the secondanchor.
 8. The surgical loading unit according to claim 7, furthercomprising a drive beam configured to translate through the anvilassembly to pivot the anvil assembly toward the cartridge assembly andcontact the knife blade of the anvil assembly to pivot the knife bladeof the anvil assembly relative to the knife blade housing of the anvilassembly.
 9. The surgical loading unit according to claim 2, wherein thesurgical buttress defines a central longitudinal axis, the portion ofthe first anchor extending over the central longitudinal axis.
 10. Thesurgical loading unit according to claim 2, wherein the first anchorextends from a location adjacent a first longitudinally-extending sideof the staple cartridge, across the staple cartridge and the surgicalbuttress, to a location adjacent a second longitudinally-extending sideof the staple cartridge.
 11. The surgical loading unit according toclaim 2, wherein the first anchor is disposed adjacent the distal endportion of the staple cartridge.
 12. The surgical loading unit accordingto claim 2, wherein the first anchor is substantially perpendicular to acentral longitudinal axis defined by the surgical buttress.
 13. Thesurgical loading unit according to claim 2, wherein the surgicalbuttress has a tissue-oriented surface defining a plane, the portion ofthe first anchor being parallel with the plane.
 14. The surgical loadingunit according to claim 12, wherein the surgical buttress defines alongitudinal axis, the portion of the first anchor being perpendicularto the longitudinal axis defined by the surgical buttress.
 15. Asurgical loading unit, comprising: a cartridge assembly; an anvilassembly including: an anvil plate defining a plurality of stapledeforming pockets; and a cover plate secured to the anvil plate, theanvil assembly and the cartridge assembly together forming a toolassembly and arranged so that the cartridge assembly and the anvilassembly are relatively movable to a position for clamping tissuetherebetween; a knife blade housing disposed between a distal endportion of the cover plate and a distal end portion of the anvil plate,the knife blade housing defining a recess; and a knife member attachedto the knife blade housing and configured to move relative to the knifeblade housing; a surgical buttress configured to be positioned over atissue-oriented surface of the anvil plate so that the surgical buttressoverlies the plurality of staple deforming pockets; and a first anchorhaving a portion extending over and across the surgical buttress,wherein the first anchor is configured to secure the surgical buttressto the anvil plate, the first anchor having an end portion disposed inthe recess of the knife blade housing.
 16. The surgical loading unitaccording to claim 15, further comprising a drive beam configured totranslate through the anvil assembly to move the anvil assembly towardthe cartridge assembly and contact the knife blade to pivot the knifeblade relative to the knife blade housing.
 17. The surgical loading unitaccording to claim 15, wherein the anvil plate defines a pair ofrecesses formed therein for engaging the first anchor.
 18. The surgicalloading unit according to claim 17, wherein at least one recess of thepair of recesses is formed in a longitudinally-extending lateral sidesurface of the anvil plate and frictionally engages the end portion ofthe first anchor.
 19. The surgical loading unit according to claim 15,wherein the surgical buttress defines a central longitudinal axis, theportion of the first anchor extending over the central longitudinalaxis.
 20. The surgical loading unit according to claim 15, wherein thesurgical buttress has a tissue-oriented surface defining a plane, theportion of the first anchor being parallel with the plane.
 21. Thesurgical loading unit according to claim 20, wherein the portion of thefirst anchor is coplanar with the plane of the tissue-oriented surfaceof the surgical buttress.